Cabinets and enclosures are used to house and protect a wide variety of items, which may vary greatly in size and shape. A variety of cabinet configurations have been developed for the protection of items such as electrical and electronic assemblies, vacuum tubes and other easily damaged components of the past, and state-of-the-art compact high speed hybrid and digital circuits. Today, electronic assemblies differ as to the space and proportions necessary to house them. While a cabinet the size of several cubic feet may be necessary to house a high voltage system or a multi-server system, a cabinet the size of a pack of cigarettes may be needed to house a compact electrical or embedded electronics arrangement. There are many cabinet and enclosure structures available in many sizes. However, users of such enclosures are limited to either choosing a standard size enclosure, which may be too large for their applications; or fabricating a custom size enclosure, which may require welding, a large amount of machining, or high tooling costs.
In many situations, it is beneficial to use a cabinet with multiple compartments. For example, in the case of an electrical circuit or circuits, it may be desirable to separate a high voltage section from a low voltage section, or a particularly noise-sensitive circuit from other circuits. In such cases, custom fabrication becomes considerably more difficult. Means for construction of a cabinet or enclosure or a set of modular interconnected cabinets or enclosures that provides strength, ease of assembly, and appropriate size for a particular application, large or small, has yet to be realized.
A number of attempts have been made to provide a cabinet which satisfies these criteria, but typically the cost or the complexity, the size, versatility or strength has been less than desirable. By way of example, the following U.S. patents disclose either welded or modular frame assemblies representative of cabinet structures developed in the prior art:    U.S. Pat. No. 2,167,525: Rosendale    U.S. Pat. No. 5,066,161: Pinney    U.S. Pat. No. 3,265,419: Durnbaugh, et al.    U.S. Pat. No. 3,182,846: La Kaff    U.S. Pat. No. 3,919,603: Salvati
The patents to Rosendale and Durnbaugh et al both disclose welded cabinet structures. Rosendale employs gussets, triangular pieces of metal, welded in each corner to hold three mutually perpendicular struts in a corner arrangement. Durnbaugh et al eliminates such gusset members and welds the strut members directly to each other at their intersection. However, each of the three strut members which form each corner have different end cross-sectional configurations and end profiles, which complicates manufacture and construction of the frame. Additionally, four welds are desired to join the struts to create a rigid frame structure. The cabinet structures of Rosendale and Durnbaugh et al therefore, are very labor intensive.
The patents to La Kaff and Salvati disclose cabinet configurations that involve mechanical assembly. In La Kaff, side frame struts are coupled to the top and base members using engaging elements formed of generally rectangular aluminum blocks, which are attached by welding to the top and bottom members and struts. The engaging elements have frustoconical portions configured to fit snugly together. The top and base members are matted via the engaging elements, and bolted together. Both manufacturing cost and lack of versatility make this frame an undesirable alternative. Salvati et al disclose a switchgear framework including a corner tie for supporting three structural corner members together. The corner tie has three rectangular-shaped perpendicular legs with three sides and outwardly facing flanges, the three struts being slid over the leg portions. However, the struts and leg portions have different cross-sectional configurations, and the corner tie is of a generally complex configuration, such that this frame structure is not conducive to low-cost manufacturing techniques.
The Pinney patent discloses a simplified cabinet frame structure element, however, bending, cutting at angles on corners, and welding processes may be required, which are not conducive to low-cost manufacturing techniques.
In the discovered prior art, welding is commonly used to join the frame elements together. Another development is known as T-slot or 80/20 aluminum extrusion. This is a family of extruded aluminum products intended for use in rapid frame construction for enclosures and other assemblies. It is manufactured in a variety of profiles with a variety of accessories, however there are shortcomings. Accessories such as sliding wear pads are required for most assemblies. Further, a large amount of machining and accessories is required to fabricate an enclosure with multiple compartments.
It would be advancement in the art to provide an enclosure and cabinet system based on frame elements of a single particular cross-sectional shape that allows rapid, low-cost, custom fabrication of enclosures with no welding required, little or no machining required, high strength, and modularity.